Tragedy in acrylic tank w/metal halide lights!

I have a 100 gallon tank from Tenecor, it is acryllic as well and I just upgraded to MH 4 months ago. I purchased a canopy with an IceCap 4" fan in the back. The hood raises my MH lamps 1 ft. off the top of my tank and the back is almost completely open.

This was the canopy that Tenecor recommended for MH. When I ordered the hood the salesman told me that he has had customers who purchased MH without upgrading their hoods or who did not raise their MH lamps at least 1 ft. off the top of the tank and their tanks failed, even with eurobracing.

This freaks me out a little, but hopefully my canopy and fan combo with the bulbs that high off the top will help.
 
Wow! I am sorry for the issues you've had but consider what you have posted good information. I personally have been looking for larger place and have thought greatly about getting a custom acrylic tank built. This sets me back a little and may have to stick with glass.
 
The story will end happily, starting Monday

Even after talking to Clarity Plus, I decided to purchase another acrylic tank to replace it. Unfortunately, the story did get sadder: When my tank was made, Clarity Plus' 100G flat-back-hex was exactly 59 1/2" long. I purchased the acrylic stand and canopy when I bought the tank. About 5-6 years ago, they decided that it was stupid to have a tank that was 1/2" shorter than everyone else, so they started making all of their 100G fbh tanks exactly 60" long. If I were to purchase an "in stock" tank, it would be 1/2" too long to fit into the stand. A new stand runs about $900, so replacing the stand wasn't going to be the answer. Unfortunately, I had to have a tank custom-made so it would fit into my stand. They recommended that if I were to stick with my metal halide lights (which I am), that the top of the tank should be 1/2" instead of the standard 3/8". On tanks up to 100G, 3/8" is acceptable, but any larger, and the thickness goes to 1/2".
Here I'm going to spend about $1,000, just to get my aquarium looking exactly like it did the day the seam let loose. It seemed to be such a sad way to spend a grand, so I decided to have them make the tank 6" taller, making the capacity about 125 gallons, plus all of the acrylic is 1/2" thick.
I got a call from the trucking company yesterday (Friday), and the tank will be delivered on Monday. It took about 5 weeks to have the tank custom made, not by Clarity Plus, but by the guy who originally owned Clarity Plus before selling it to Casco in California. It was going to cost $300 to ship the tank from CA to GA, and having the tank made at the original Clarity Plus factory in Hudsonville, MI saved me $75 in shipping alone. Because I went from 3/8" sides to 1/2" sides, added an extra 6" in height, my early Christmas present to myself set me back a little over $1,350.
Note: The back of the tank did not bow because of poor construction, or too much stress on it. It bowed because the acrylic cement let loose, causing the back panel to bow from the water pressure, until it cracked on both sides from the stress, letting water run out of the tank.
I was able to line up the seems again, using C-clamps, and other tools which pressed against the wall of the house, forcing the tank back to re-align itself with the top. I re-cemented it, prayed a lot, then filled it up just as if nothing had happened. That worked until about a week ago, when it let go again. I had a brace against the back wall, to keep the acrylic panel from bowing if the joint failed again. I wanted to be able to use my prefilter, chiller, protein skimmer, and short of drilling new drain holes about 5" down from the top, it seemed like my best choice. Nothing died, but I aged about 10 years in a very short time.
I'm going to ask for some advice on the best way to totally tear down the old tank, and set up the new tank. I have ich in the tank right now, and lots of live rock, so I plan on using hyposalinity in the new tank before I add any fish. Naturally, I'll have to move my clam, coral band shrimp, brittle star, and possibly my leather coral, and replace them after the salinity is back to normal parameters (1.023-1.025).
Thanks for the condolences, it has been a real ordeal, but I really look forward to setting up my new tank. It's been so long since I've been able to completely "start over".
Jim H.
 
I thought that the single ended bulbs had UV shielding built in, and that the DE bulbs used a glass shield over the reflector assembly that filtered the UV.

Folks:

My research predicates that acrylic (unlike PVC) is inert with respect to UV.

If anyone has evidence to the contrary please post.

TR
 
It's not the acrylic that's degrading, it's the bonding agent (cement) that gets degraded by UV rays. It literally makes the seam "let go". It would never have happened if I were astute enough to notice that the seam wasn't clear, like it is on properly bonded joints. My acrylic covers each have 2 supports bonded to them to keep them from bowing. After my fiasco with my tank, I put some acrylic cement in a syringe, and re-bonded the seams that appeared to be letting go. The "water like" cement was just sucked into the open spaces in the joint, attesting to the fact that the bonding agent had either let go, or disappeared. The joints immediately turned "clear", indicating a solid bond between both pieces of acrylic.
The person I spoke to at Clarity Plus wasn't just a girl on the switchboard, he was a district manager with over 15+ years in the business, so I have no reason to doubt what he told me.

On a 100G tank that has 3/8" acrylic, they recommended I go with a 1/2" top instead. It makes sense that the UV rays will have to travel 1/2" before they get to the glue, instead of having to go through only 3/8"
 
It's not the acrylic that's degrading, it's the bonding agent (cement) that gets degraded by UV rays.

jhoeger:

Thanks a bunch for posting this!!

Tenecor indicates that the seams in my tank are "acrylic welded" (I could not ascertain the definition of this term unfortunately) but the side walls of my tank appear to "somehow be welded" to the bowfront.

TR
 
Tenecor indicates that the seams in my tank are "acrylic welded" (I could not ascertain the definition of this term unfortunately) but the side walls of my tank appear to "somehow be welded" to the bowfront.[/qoute]

Your tank has a cold weld seam that has a special glue/gap filler that welds the seams together. This same joint is used in big public aquariums between 2 viewing panes and then buffed out to become invisible.

The heat causes bowing along with the force of the weight of the water. Bowing stresses the joints and heat also helps them fail. Then the UV degrades the glue as mentioned.

If UV has no effect on acrylic then can someone tell my the acrylic used to turn yellow before they upgraded to better plastics?
 
If UV has no effect on acrylic then can someone tell my the acrylic used to turn yellow before they upgraded to better plastics?

I can vouch that UV light does things to acrylic. I tan in tanning beds - UV light from the bulbs which my brain and reading while in there tells me they are basically the same as used for marine tank. Also the part that covers the bulbs which a person lays on are acrylic. Granted it is thinner acrylic and probably a lot closer to the bulbs, but the acrylic does indeed need to be MH could potentially do to it.

However, I'm sorry to hear about the OP's tragedy of the tank. At least you were in a position to shell out that much cash on a new tank. It would be a shame if you had not been.
 
Mr. Firemouth,
What is eurobracing? Mine is covered almost completely with a 1/2" sheet of acrylic with 3 small holes cut out for access. Is this eurobracing?
eurobracing001.jpg

Thanks,
Tom

>>If you insist on acrylic tanks, then make sure it is a thicker piece of acrylic, has Eurobracing, and that there are no cracks, webbing, or air bubbles in the seams.
 
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